Abstract: A excessively-conjugated heat assembly and a mechanical clamp device were used to achieve the radial pre-strain of disk-shaped LY12 samples. In the experiment, the LY12 samples were impacted by the flyer plates driven by a one-stage light-gas gun, and spall signals of the samples in several pre-strain states were measured by VISAR. The experimental results show that the spall strengths are 1.13, 0.935, 0.755 and 0.643 GPa respectively corresponding to the pre-strains of 0, 25110-6, 1 10810-6 and 1 88610-6 when the samples are impacted by the flyer plates with 500 m/s. The pre-stress (pre-strain) reduces the spall strength of LY12 aluminum obviously. It is confirmed that the spall strength is closely related to the initial stress. It is helpful for the future research on materials spallation in multi-dimensional strain states.